Cabin air filter: when to change it and why it matters
You turn the fan up to full but only a weak stream of air reaches the cabin, or a stale smell appears every time the air conditioning starts. The cause is often a blocked cabin air filter car owners rarely think about, a small part that has a big effect on the quality of the air you breathe in the car. In this article we look at what it does, when to change it, the signs of a clogged filter and how much a replacement costs.
If airflow feels weak or a smell appears, a few minutes is all it takes: locate your nearest Motrio garage and have the cabin air filter replaced.
What does a cabin air filter do and when should it be changed?
The cabin air filter traps dust, pollen, soot and fine particles before air enters the cabin through the vents. Many drivers choose an activated carbon filter, which also absorbs odours and exhaust gases.
The general rule is to replace the cabin air filter every 15,000 km or once a year, whichever comes first. If you drive mostly in town, on dusty roads or in areas with high pollen, it is worth doing it sooner, because the filter clogs faster. The right interval depends on how the car is actually used, not just the calendar.
Changing it on time also protects the air conditioning system. A clogged filter reduces airflow, makes the fan work harder and encourages mould on the evaporator. The result is bad smells and weaker cooling, exactly when you need it most in summer.
Knowing where it sits helps you not to overlook it. On most cars the cabin air filter is behind the glovebox on the passenger side or under the windscreen, near the base of the wipers. If it looks dark grey or full of leaves and dust, it is time to replace it: the simplest option is to book a check at your nearest Motrio garage, where the technician fits the right filter and makes sure it seals correctly.
Signs of a clogged cabin air filter and replacement cost
The signs are easy to recognise. Airflow drops even with the fan on full, the windows mist up more quickly and a damp or stale smell appears when the system starts. Allergy sufferers often feel worse in the car, a sign the filter no longer holds back pollen and dust as it should.
At a glance, the signs to watch for are:
- Poor airflow from the vents, even with the fan on full
- A damp or stale odour from the vents
- Windows that mist up or ice over more quickly
- Increased fan noise as it works harder
- Weaker heating or cooling
- Worsening allergy symptoms inside the car
The cost is modest. The cabin air filter on its own usually costs between £10 and £30 depending on the model and type, standard or activated carbon. With labour, a full replacement at a garage comes to between £25 and £55 and takes between 15 and 30 minutes.
It makes sense to combine the filter change with regular servicing. During a car service it is usually replaced at the annual check-up, and pairing it with an oil and oil filter change and a new engine air filter keeps the car in better overall condition. If you have an air con recharge in summer, it is also the ideal time to fit a fresh filter and get back to clean air.
Which filter to choose depends on your needs. A standard filter holds back dust and pollen and is the cheapest option. An activated carbon filter costs a few pounds more but also absorbs smells and exhaust gases, useful in town or in heavy traffic. Either way it is best to fit a part that matches the manufacturer’s original equipment (OE) reference, because a filter that does not seal properly lets unfiltered air slip past the edges. If smells linger after replacement, the filter is not the cause: an air conditioning clean is usually what clears them.
Cabin air filter replacement at a Motrio garage
Motrio garages handle cabin air filter replacement with parts that meet your manufacturer's specifications, and check the state of the air conditioning during the same visit.
Motrio is a network of independent garages backed by the Renault Group, with short lead times and clear pricing, and offers a 1-year warranty on parts and labour. If airflow has dropped or an unpleasant smell appears on start-up, find your nearest Motrio garage and breathe clean air on every journey.